title: microRNA-10b enhances pancreatic cancer cell invasion by suppressing TIP30 expression and promoting EGF and TGF-β actions.
abstract: Increased microRNA-10b (miR-10b) expression in the cancer cells in pancreatic ductal adenocarcinoma (PDAC) is a marker of disease aggressiveness. In the present study, we determined that plasma miR-10b levels are significantly increased in PDAC patients by comparison with normal controls. By gene profiling, we identified potential targets downregulated by miR-10b, including Tat-interacting protein 30 (TIP30). Immunoblotting and luciferase reporter assays confirmed that TIP30 was a direct miR-10b target. Downregulation of TIP30 by miR-10b or siRNA-mediated silencing of TIP30 enhanced epidermal growth factor (EGF)-dependent invasion. The actions of miR-10b were abrogated by expressing a modified TIP30 cDNA resistant to miR-10b. EGF-induced EGF receptor (EGFR) tyrosine phosphorylation and extracellular signal-regulated kinase phosphorylation were enhanced by miR-10b, and these effects were mimicked by TIP30 silencing. The actions of EGF in the presence of miR-10b were blocked by EGFR kinase inhibition with erlotinib and by dual inhibition of PI3K (phosphatidylinositol 3'-kinase) and MEK. Moreover, miR-10b, EGF and transforming growth factor-beta (TGF-β) combined to markedly increase cell invasion, and this effect was blocked by the combination of erlotinib and SB505124, a type I TGF-β receptor inhibitor. miR-10b also enhanced the stimulatory effects of EGF and TGF-β on cell migration and epithelial-mesenchymal transition (EMT) and decreased the expression of RAP2A, EPHB2, KLF4 and NF1. Moreover, miR-10b overexpression accelerated pancreatic cancer cell (PCC) proliferation and tumor growth in an orthotopic model. Thus, plasma miR-10b levels may serve as a diagnostic marker in PDAC, whereas intra-tumoral miR-10b promotes PCC proliferation and invasion by suppressing TIP30, which enhances EGFR signaling, facilitates EGF-TGF-β cross-talk and enhances the expression of EMT-promoting genes, whereas decreasing the expression of several metastasis-suppressing genes. Therefore, therapeutic targeting of miR-10b in PDAC may interrupt growth-promoting deleterious EGF-TGF-β interactions and antagonize the metastatic process at various levels.
authors.affiliation: Departments of Medicine, Biochemistry and Molecular Biology, Indiana University School of Medicine, the Melvin and Bren Simon Cancer Center and the Pancreatic Cancer Signature Center, Indianapolis, IN, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ouyang
authors.affiliation: Departments of Medicine, Biochemistry and Molecular Biology, Indiana University School of Medicine, the Melvin and Bren Simon Cancer Center and the Pancreatic Cancer Signature Center, Indianapolis, IN, USA.
authors.forename: J
authors.initials: J
authors.lastname: Gore
authors.affiliation: Departments of Medicine, Biochemistry and Molecular Biology, Indiana University School of Medicine, the Melvin and Bren Simon Cancer Center and the Pancreatic Cancer Signature Center, Indianapolis, IN, USA.
authors.forename: S
authors.initials: S
authors.lastname: Deitz
authors.affiliation: Departments of Medicine, Biochemistry and Molecular Biology, Indiana University School of Medicine, the Melvin and Bren Simon Cancer Center and the Pancreatic Cancer Signature Center, Indianapolis, IN, USA.
authors.forename: M
authors.initials: M
authors.lastname: Korc
mesh_terms: D000123:Acetyltransferases / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001483:Base Sequence; D001665:Binding Sites; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D004815:Epidermal Growth Factor / Q000502:physiology; D000069347:Erlotinib Hydrochloride; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000090062:Kruppel-Like Factor 4; D008297:Male; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000502:physiology*; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D011799:Quinazolines / Q000494:pharmacology; D034622:RNA Interference; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000502:physiology
chemical_list: D000970:Antineoplastic Agents; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; C547183:MIRN10 microRNA, human; D035683:MicroRNAs; D011799:Quinazolines; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D004815:Epidermal Growth Factor; D000069347:Erlotinib Hydrochloride; D000123:Acetyltransferases; C111246:HTATIP2 protein, human